Critter of the Week: Grizzly Bear

  • Common name: Grizzly bear
  • Scientific name: Ursus arctos horribilis
  • Type: Mammal
  • Diet: Omnivore
  • Status: Threatened
  • Geographic range: North America, select locations
  • Size: 5-8 feet, 800 pounds
  • Life expectancy: 25 years
(Photo credit: North American Bear Center)

In memory of going back to school, I’ve been thinking a lot about our mascot, the California grizzly bear. Unfortunately, that bear is extinct, so I guess the generic North American grizzly bear will have to do. Just as we “bears” are preparing to hunker down in our studies, the grizzly bear is currently preparing to hibernate by stocking up on food and body fat. 

Like any other animal that hibernates, grizzly bears are voracious eaters during the summer and fall. Their sharp canines are what we see up front, but they also possess molars in the back to grind up plants. Grizzlies are omnivorous; they dabble in the meat of salmon, domestic farm animals, and deer while grazing on grass, berries, and roots. For such large animals, the bulk of their diet is surprisingly plant-based. These bears run fast when hunting, reportedly reaching speeds up to 35 miles an hour. Campers are especially warned to keep their distance from baby cubs, since their mothers are fiercely overprotective. Seriously, don’t think you can outrun this

The grizzly bear is a North American subspecies of the brown bear, according to National Geographic. The entire western United States, Great Plains, and parts of Mexico used to be their home, but today, they only reside in a measly 2 percent of their original range. In 1975, when the grizzly bear was placed under the Endangered Species Act, there were less than 1,000 of them in the lower 48 states! The near-decimation of the grizzly bear is largely attributed to the presence of the westward-moving settlers that feared and profited from bears.

The grizzly bear range has greatly decreased (Photo credit: Center for Biological Diversity)

Most grizzly bears today reside in Alaska, but there are many efforts to rebuild the bear population in the lower 48 states. Under the Endangered Species Act, bears are protected by law from harm, harassment, or being killed (with the exception of self-defense). Recovery plans are underway in six recovery ecosystems: Greater Yellowstone, Northern Continental Divide, Cabinet-Yaak, Selkirk, North Cascades, and Bitterroot. For more current news on grizzly bear recovery, visit their U.S. Fish and Wildlife Services page.

Grizzly bears fishing for salmon (Photo credit: iStock)

When these bears are a nuisance to ranchers and campers, why bother to rebuild their populations? Well, bears play a critical role in their ecosystems. Being frequent foragers, they stir up dirt with their paws and disperse seeds through their feces. The salmon they catch provides food for birds and smaller predators, as well as a nitrogen source for the forest. Bears are also apex predators, which prevents mesopredator release. Mesopredators, which are often herbivores like deer, can decimate an ecosystem’s fauna if their population is not kept in check by apex predators. A healthy bear population means a healthy ecosystem, with the two mutually supporting each other.

One interesting tidbit about these bears is that the female gives birth to cubs in the winter, rather than the spring. The blastocysts (very early bear cubs) of pregnant grizzlies undergo “delayed implantation” while mama bear builds up her body weight, a process that occurs in all bear species. If the pregnant mother does not reach a threshold body weight for a successful pregnancy, the blastocysts will not implant in the mother. This means mama bear has a pretty short pregnancy for an animal of her size!

Grizzly bear mother and her cubs (Photo credit: iStock)

Grizzly bears are powerful, top-of-the-food-chain predators — no wonder they serve as mascots, representing strength and intelligence. At the same time, they manage to look cute and cuddly, evident in the teddy bears frequently gifted to significant others and young children. These creatures could use our help in the protection of their well-being and habitat. For more information, visit organizations like the Center for Biological Diversity, Adopt-a-Wildlife Acre Program, and Defenders of Wildlife. As we always say in Berkeley, “go bears!” 

(Photo credit: Robin Silver, Center for Biological Diversity)

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